Bumbo approached his teacher with a concerned look on his face. “Teacher,” he said, “some commas seem optional. How do I know whether or not to use them?”
In response, the teacher asked him, “Two bridges cross the river. One bridge is missing steps, and the other is whole. Which do you use?”
The Comma Lesson:
Some commas are required, and some seem optional. However, if some of the commas are missing, the reader might get confused. The teacher wants Bumbo to choose the option that has the greatest chance of helping the reader understand the sentence. This means Bumbo needs to put in all the commas, even the optional ones.
Applying the Comma Lesson:
Let’s look at two examples where the comma seems optional.
1. According to this, transcription service can take a long time.
This example has a comma to separate the introductory description from the main sentence (Zen Comma Rule G). Some style guides and writing instructors claim that you only need a comma in this place if the introductory description is short, such as fewer than 5 words.
The descriptive phrase here is only 3 words: “According to this.” Thus, those guides and instructors would claim that this example doesn’t need a comma. They would argue for “According to this transcription service can take a long time.”
Here’s the problem. Without the comma, a reader may interpret this multiple ways. For example, the reader may think the sentence is structured this way:
Description: According to this transcription
Main sentence: service can take a long time
Without the comma in place, the reader may not know which word is the subject, which is the fundamental purpose of the comma here. Is the subject “transcription service” or just “service”? The comma lets the reader know when the description is finished and the main sentence will begin.
2: I am a biker, and a runner can’t catch me.
This example has a comma before the conjunction (“and”) that joins two independent clauses (Zen Comma Rule D).
Some style guides and writing instructors claim you don’t need that comma if the independent clauses are short. Of course, they don’t define “short.” The two independent clauses here are 4 and 5 words, respectively. If 4 words is “short,” then those guides and instructors may argue for “I am a biker and a runner can’t catch me.”
Here’s the problem. Upon reading this, the reader may think that I am both a biker and a runner, as in, “I am a biker and a runner.” This seems like a complete thought. Then the reader gets to “can’t catch me,” which doesn’t make sense. The reader will have to re-read the sentence and try to figure it out.
Without the comma in place, the reader may have difficulty separating the two main ideas in the sentence. Most likely, the reader will figure it out upon re-reading, but that’s more work than the reader should have to do. Also, the reader will be thinking about the writing, not the content. The comma tells the reader when the first main idea is finished and the next one begins.
What I Do with Optional Commas
I take advice from Bumbo’s comma teacher. To increase clarity and the potential for reader understanding, I put in all the commas, even the commas that seem optional.
Need help with commas? Get Zen Comma, an instructive reference guide on the 17 major uses and misuses of commas, available in PDF and Kindle formats. Read more about Zen Comma.